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Fish may have evolved from an animal similar to a coral-like sea squirt (a tunicate), whose larvae resemble early fish in important ways. The first ancestors of fish may have kept the larval form into adulthood , as some sea squirts do today, although this path cannot be proven.
The evolution of fishes took place over a timeline which spans the Cambrian to the Cenozoic, including during that time in particular the Devonian, which has been dubbed the "age of fishes" for the many changes during that period. The Late Devonian extinctions played a crucial role in shaping the evolution of fish, or vertebrates in general. [1]
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
Scientists are calling it the “the most rapid radiation event among vertebrates” ever discovered.
Beginning of animal evolution. [54] [55] 720–630 Ma Possible global glaciation [56] [57] which increased the atmospheric oxygen and decreased carbon dioxide, and was either caused by land plant evolution [58] or resulted in it. [59] Opinion is divided on whether it increased or decreased biodiversity or the rate of evolution. [60] [61] [62 ...
Roughly 100 million years before Gaiasia existed, the first land vertebrates had evolved from fish with fleshy fins. These are called the stem tetrapods. They lived an amphibious lifestyle though ...
The first tetrapods probably evolved in the Emsian stage of the Early Devonian from Tetrapodomorph fish living in shallow water environments. [ 36 ] [ 37 ] The very earliest tetrapods would have been animals similar to Acanthostega , with legs and lungs as well as gills, but still primarily aquatic and unsuited to life on land.
Inside the stout fins of a fish that prowled the shallow waters of an estuary in what is now eastern Canada about 380 million years ago, scientists have found what they call the evolutionary ...